JPWO2016181591A1 - Epoxy resin composition - Google Patents

Abstract

The epoxy resin composition of the present invention is a resin composition containing an epoxy resin, a curing agent, and liquid rubber. And when the said epoxy resin composition hardens | cures, the phase-separation structure isolate | separated into the 2 or more phase was formed, and the hardness measured with the type E durometer prescribed | regulated to JISK6253 is 80 or less. Since the epoxy resin composition has a phase separation structure composed of a plurality of phases having relatively different contents of the epoxy resin and the liquid rubber, the hardness is lowered and the flexibility can be increased.

Description

  The present invention relates to an epoxy resin composition. Specifically, the present invention relates to an epoxy resin composition having high flexibility.

  The epoxy resin becomes a three-dimensional cross-linked cured product when reacted with a curing agent, and the obtained cured product has characteristics such as high mechanical strength, heat resistance, electrical insulation and chemical resistance. Therefore, epoxy resins are widely used from the building materials field to the electronic materials field as paints, adhesives, laminates, sealing materials and the like. However, since the epoxy resin is three-dimensionally cross-linked, it is known that the cured product is brittle and has low impact resistance and flexibility. Further, for example, in a liquid sealing material and a flexible printed wiring board used for a semiconductor package material, an epoxy resin excellent in flexibility is required.

  Therefore, in order to improve flexibility, attempts have been made to introduce a highly flexible skeleton such as rubber modification or silicone modification into an epoxy resin to improve the properties of the resin itself. For example, Patent Document 1 discloses an epoxy resin composition comprising a bisphenol A type epoxy resin having a flexible skeleton and a polar bonding group, and a polythiol having two or more thiol groups. Thus, by including a flexible skeleton in the epoxy resin, the cured product is deformed at the portion of the flexible skeleton to have flexibility and flexibility, and stress can be absorbed.

JP 2006-36935 A

  However, it is difficult to further increase the flexibility only by including a flexible skeleton in the epoxy resin. Even if a flexible skeleton is contained, for example, when a filler is added, there is a possibility that flexibility may be impaired.

  The present invention has been made in view of such problems of the prior art. An object of the present invention is to provide an epoxy resin composition having high flexibility.

  In order to solve the above problems, an epoxy resin composition according to an embodiment of the present invention contains an epoxy resin, a curing agent, and a liquid rubber. And when the said epoxy resin composition hardens | cures, the phase-separation structure isolate | separated into the 2 or more phase was formed, and the hardness measured with the type E durometer prescribed | regulated to JISK6253 is 80 or less.

FIG. 1 is a schematic diagram for explaining a phase separation structure. (A) shows a sea-island structure, (b) shows a continuous spherical structure, (c) shows a composite dispersion structure, and (d) shows a common structure. Shows a continuous structure. FIG. 2 is a photograph showing a result of observing a cross section of the resin plate of Example 1 with a laser microscope. FIG. 3A is a photograph showing the result of observing the cross section of the resin plate of Example 1 with a microscope. FIG. 3B is a graph showing Raman spectra at points a) and b) in FIG. FIG. 4 shows the result of Raman spectroscopic analysis of the cross section of the resin plate of Example 1. (A) shows a Raman mapping image derived from a benzene ring (DGEBA), and (b) shows a Raman mapping image derived from a C═C bond (butadiene). FIG. 5 is a photograph showing a result of observing a cross section of the resin plate of Example 2 with a laser microscope. FIG. 6A is a photograph showing the result of observing the cross section of the resin plate of Example 2 with a microscope. FIG. 6B is an enlarged photograph of the range indicated by the symbol B in FIG. FIG.6 (c) is a graph which shows the Raman spectrum in the point a) of FIG.6 (b), and b point. FIG. 7 shows the result of Raman spectroscopic analysis of the cross section of the resin plate of Example 2. (A) shows a Raman mapping image derived from a benzene ring (DGEBA), and (b) shows a Raman mapping image derived from a C═C bond (butadiene). FIG. 8 is a photograph showing a result of observing a cross section of the resin plate of Example 3 with a scanning electron microscope. FIG. 9 is a photograph showing a result of observing a cross section of the resin plate of Example 4 with a scanning electron microscope.

  Hereinafter, the epoxy resin composition according to the present embodiment will be described in detail. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

  The epoxy resin composition according to this embodiment is a resin composition formed from an epoxy resin, a curing agent, and liquid rubber. And when the said epoxy resin composition hardens | cures, the phase-separated structure isolate | separated into two or more phases is formed.

  As described above, the epoxy resin becomes a three-dimensional cross-linked cured product when reacted with a curing agent, and the obtained cured product has characteristics such as high mechanical strength, heat resistance, electrical insulation and chemical resistance. . However, since the epoxy resin is three-dimensionally cross-linked, it is known that the cured product has low flexibility.

  Therefore, in the epoxy resin composition of this embodiment, liquid rubber is added to impart flexibility to the epoxy resin. The liquid rubber is a synthetic rubber that becomes a rubber elastic body by a crosslinking reaction or a chain extension reaction. And by adding such liquid rubber, it becomes possible to raise the softness | flexibility of an epoxy resin composition resulting from the softness | flexibility of liquid rubber.

  Furthermore, in this embodiment, when the epoxy resin composition is cured, a phase separation structure separated into two or more phases is formed. Specifically, it has a phase separation structure having an epoxy resin rich phase composed mainly of a cured product obtained by a reaction between an epoxy resin and a curing agent, and a liquid rubber rich phase composed mainly of a liquid rubber. By forming such a phase separation structure, the liquid rubber-rich phase is highly dispersed, the flexibility of the epoxy resin composition is increased, and it becomes possible to have flexibility. Further, by forming a phase separation structure, a liquid rubber-rich phase is included in the epoxy resin-rich phase, an epoxy resin-rich phase is included in the liquid rubber-rich phase, or an adjacent epoxy resin-rich phase. A liquid rubber-rich phase is interposed between them. Therefore, since the liquid rubber-rich phase plays a role as a buffer material, it is possible to absorb internal stress and enhance flexibility and flexibility.

  More specifically, the epoxy resin composition of the present embodiment is different from the first resin phase in which the first resin is three-dimensionally continuous and the second resin formed by the second resin. It is preferable to have a phase separation structure including a phase. And it is preferable that content of the liquid rubber contained in any one of 1st resin and 2nd resin is larger than content of liquid rubber contained in the other of 1st resin and 2nd resin. Thus, the epoxy resin composition is separated into two phases of the first resin phase and the second resin phase, and the content of the liquid rubber contained in the first resin is greater than that of the second resin, or the second resin. By making the content of the liquid rubber contained in the resin larger than that of the first resin, flexibility can be further enhanced.

  The phase separation structure in this embodiment refers to any of a sea-island structure, a continuous spherical structure, a composite dispersion structure, and a co-continuous structure. As shown in FIG. 1A, the sea-island structure is a structure in which a small volume dispersed phase 2 is dispersed in a continuous phase 1, and a structure in which fine particles or spherical dispersed phases 2 are scattered in the continuous phase 1. It is. As shown in FIG. 1B, the continuous spherical structure is a structure in which approximately spherical dispersed phases 2 are connected and dispersed in the continuous phase 1. As shown in FIG. 1C, the composite dispersed structure is a structure in which the dispersed phase 2 is dispersed in the continuous phase 1 and the resin constituting the continuous phase 1 is further dispersed in the dispersed phase 2. As shown in FIG. 1D, the co-continuous structure is a structure in which the continuous phase 1 and the dispersed phase 2 form a complicated three-dimensional network.

  In addition, the phase separation structure such as the sea-island structure, continuous spherical structure, composite dispersion structure, and co-continuous structure is determined by the curing conditions such as the curing speed and reaction temperature of the resin composition, and the compatibility and blending ratio of the epoxy resin and the liquid rubber. Can be obtained by controlling. Further, in the epoxy resin composition of the present embodiment, the phase separation structure such as the sea-island structure or the co-continuous structure described above is adjusted by adjusting the content ratio of the resin component composed of the epoxy resin, the curing agent and the liquid rubber, and the filler. Can be selected.

  As described above, in the epoxy resin composition, the content of the liquid rubber contained in the first resin constituting the first resin phase is greater than the second resin constituting the second resin phase, or the second resin contains It is preferable that the content of the liquid rubber contained is greater than that of the first resin. That is, it is preferable that the content of the liquid rubber contained in the first resin is larger than that of the second resin by mass ratio, or the content of the liquid rubber contained in the second resin is larger than that of the first resin by mass ratio. . Further, it is preferable that the content of the liquid rubber contained in the first resin is larger than that of the second resin in a molar ratio, or the content of the liquid rubber contained in the second resin is larger than that of the first resin in the molar ratio. .

  In the epoxy resin composition, the first resin constituting the first resin phase is mainly composed of one of the epoxy resin and the liquid rubber, and the second resin constituting the second resin phase is the other of the epoxy resin and the liquid rubber. It is also preferable to use it as a main component. That is, the first resin preferably contains 50% by mass or more of either an epoxy resin or liquid rubber, more preferably 70% by mass or more, and particularly preferably 90% by mass or more. Moreover, it is preferable that 2nd resin contains 50 mass% or more of the other of an epoxy resin and liquid rubber, it is more preferable to contain 70 mass% or more, and it is especially preferable to contain 90 mass% or more.

  Here, in the above-described phase separation structure, the epoxy resin-rich phase mainly composed of an epoxy resin preferably contains not only a cured product obtained by reacting an epoxy resin and a curing agent but also a liquid rubber. In other words, the epoxy resin-rich phase is mainly composed of an epoxy resin, but since it also contains liquid rubber, the flexibility of the epoxy resin-rich phase itself is improved. It becomes possible to raise more. Conversely, the liquid rubber-rich phase mainly composed of liquid rubber preferably contains not only the liquid rubber but also a cured product obtained by reacting an epoxy resin and a curing agent. That is, the liquid rubber-rich phase contains liquid rubber as a main component, but since the cured product also contains the liquid rubber-rich phase, the hardness of the liquid rubber-rich phase is improved, so that the durability of the liquid rubber-rich phase can be increased.

  When the epoxy resin composition of this embodiment has a sea-island structure, the continuous phase 1 may be an epoxy resin-rich phase or a liquid rubber-rich phase. However, when the continuous phase 1 is a liquid rubber rich phase, the liquid rubber rich phase covers the epoxy resin rich phase. Therefore, since the ratio of a liquid rubber rich phase increases, the hardness of an epoxy resin composition falls more and it becomes possible to raise a softness | flexibility further.

  In this embodiment, a well-known thing can be used for an epoxy resin. For example, a bisphenol A type epoxy resin obtained by a condensation reaction between bisphenol A and epichlorohydrin can be used. Further, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, naphthalene diol type epoxy resin, phenol novolac type epoxy resin can be used. Cresol novolac type epoxy resins, bisphenol A novolak type epoxy resins, cycloaliphatic epoxy resins, and heterocyclic epoxy resins (triglycidyl isocyanurate, diglycidyl hydantoin, etc.) can also be used. Furthermore, modified epoxy resins obtained by modifying these epoxy resins with various materials can also be used. Moreover, halides such as bromides and chlorides of these epoxy resins can also be used. One of these epoxy resins may be used alone, or two or more of them may be used in combination. Among these, the epoxy resin is particularly preferably a bisphenol A type epoxy resin.

  As the curing agent for curing the epoxy resin, any compound having an active group capable of reacting with an epoxy group can be used. Known epoxy curing agents can be used as appropriate, but compounds having an amino group, an acid anhydride group, or a hydroxyphenyl group are particularly suitable. For example, dicyandiamide and its derivatives, organic acid hydrazine, amine imide, aliphatic amine, aromatic amine, tertiary amine, polyamine salt, microcapsule type curing agent, imidazole type curing agent, acid anhydride, phenol novolac, etc. . A hardening | curing agent may be used individually by 1 type of these, and may be used in combination of 2 or more type. Among these, the curing agent is particularly preferably an aliphatic amine.

  Aliphatic amines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, hexamethylenediamine, 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, iminobispropylamine, bis (hexa Methylene) triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-hydroxyethylethylenediamine, tetra (hydroxyethyl) ethylenediamine and the like. Also included are triethylene glycol diamine, tetraethylene glycol diamine, diethylene glycol bis (propylamine), polyoxypropylene diamine, polyoxypropylene triamines, and the like.

  Various curing accelerators can be used in combination with the above-described curing agent. Examples of the curing accelerator include tertiary amine-based curing accelerators, urea derivative-based curing accelerators, imidazole-based curing accelerators, and diazabicycloundecene (DBU) -based curing accelerators. Also, organophosphorus curing accelerators (for example, phosphine curing accelerators), onium salt curing accelerators (for example, phosphonium salt curing accelerators, sulfonium salt curing accelerators, ammonium salt curing accelerators, etc.) Can be mentioned. Furthermore, a metal chelate type | system | group hardening accelerator, an acid, and a metal salt type hardening accelerator etc. can be mentioned.

  In the present embodiment, the liquid rubber may be a liquid polymer whose raw material polymer is liquid, and a liquid polymer exhibiting rubber elasticity after processing. As the raw material polymer, for example, at least one selected from the group consisting of butadiene, isoprene, acrylonitrile-butadiene, and styrene-butadiene can be used. Therefore, the liquid rubber preferably contains at least one selected from the group consisting of butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, and styrene-butadiene rubber. The liquid rubber is more preferably composed of at least one selected from the group consisting of butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, and styrene-butadiene rubber. Among these, the liquid rubber is particularly preferably made of butadiene rubber.

In addition, in order for liquid rubber to exhibit favorable rubber-like elasticity after processing, it is necessary to finally have a three-dimensional network structure. Therefore, it is preferable that the molecular terminal in the liquid rubber has a functional group. Examples of such functional groups include hydroxy groups (—OH), carboxy groups (—COOH), thiol groups (—SH), amino groups (—NH ₂ , —NHR, —NRR ′), halogen groups (— And at least one selected from the group consisting of Cl, -Br, -I). In addition, it is especially preferable that the terminal of the molecule | numerator in liquid rubber has a hydroxyl group.

  When the terminal of the molecule in the liquid rubber has a functional group, not only the three-dimensional network structure can be easily formed, but also the compatibility between the epoxy resin and the liquid rubber can be improved. And, when these compatibility increases, even when the epoxy resin and the curing agent react to form a phase structure, the liquid rubber tends to remain inside the epoxy resin rich phase. Therefore, the flexibility of the epoxy resin rich phase can be improved due to the flexibility of the liquid rubber.

  In the epoxy resin composition of the present embodiment, the volume ratio of the component composed of the epoxy resin and the curing agent and the liquid rubber is 80:20 to 20:80 (the component composed of the epoxy resin and the curing agent: liquid rubber). Is more preferable, and 70:30 to 60:40 is more preferable. When the volume ratio of the component consisting of the epoxy resin and the curing agent and the liquid rubber is within this range, the epoxy resin composition can effectively form a phase separation structure. Moreover, when the volume ratio of the liquid rubber component in an epoxy resin composition is 20 volume% or more, it becomes possible to raise the softness | flexibility of an epoxy resin composition and to suppress the improvement of hardness. Moreover, when the volume ratio of a liquid rubber component is 80 volume% or less, it becomes possible to prevent that the sclerosis | hardenability of an epoxy resin composition falls and it becomes weak.

  The epoxy resin composition of this embodiment may further contain a filler in addition to the epoxy resin, the curing agent and the liquid rubber. Since the filler has higher thermal conductivity than the epoxy resin and liquid rubber, the thermal conductivity of the epoxy resin composition can be improved by containing the filler. In addition, since the epoxy resin, the curing agent, and the liquid rubber have electrical insulation, when the filler has electrical insulation, the resulting epoxy resin composition may also have electrical insulation. It becomes possible.

  The filler may be dispersed throughout the epoxy resin composition, or may be unevenly distributed in one of the epoxy resin rich phase and the liquid rubber rich phase. The uneven distribution in one of the epoxy resin rich phase and the liquid rubber rich phase reduces the distance between the filler and the filler. Therefore, the contact between the fillers increases and a heat conduction path is easily formed, so that the heat conductivity of the epoxy resin composition can be improved.

Such a filler is preferably made of an inorganic compound, for example, at least one selected from the group consisting of borides, carbides, nitrides, oxides, silicides, hydroxides and carbonates. preferable. Specifically, the filler is, for example, magnesium oxide (MgO), aluminum oxide (alumina, Al ₂ O ₃ ), boron nitride (BN), aluminum nitride (AlN), aluminum hydroxide (Al (OH) ₃ ). , Silicon dioxide (SiO ₂ ), magnesium carbonate (MgCO ₃ ), magnesium hydroxide (Mg (OH) ₂ ), calcium carbonate (CaCO ₃ ), clay, talc, mica, titanium oxide (TiO ₂ ), zinc oxide (ZnO At least one selected from the group consisting of: From the viewpoint of thermal conductivity and ease of filling, the filler preferably contains at least one selected from the group consisting of MgO, Al ₂ O ₃ , BN, and AlN. Moreover, it is particularly preferable that the filler contains at least one selected from the group consisting of MgO, Al ₂ O ₃ and BN. The filler is magnesium oxide (MgO), aluminum oxide (Al ₂ O ₃ ), boron nitride (BN), aluminum nitride (AlN), aluminum hydroxide (Al (OH) ₃ ), silicon dioxide (SiO ₂ ). , Magnesium carbonate (MgCO ₃ ), magnesium hydroxide (Mg (OH) ₂ ), calcium carbonate (CaCO ₃ ), clay, talc, mica, titanium oxide (TiO ₂ ), and zinc oxide (ZnO). The particle | grains which consist of at least 1 type may be sufficient.

  The amount of the filler contained in the epoxy resin composition is not particularly limited. However, it is preferable that the quantity of a filler is 0-60 volume% of the whole epoxy resin composition. When the amount of the filler is within this range, the epoxy resin composition can effectively form a phase separation structure. In addition, even if there is much quantity of a filler, it is possible to improve the softness | flexibility of an epoxy resin composition. However, when the amount of the filler is excessive, the phase separation structure of the epoxy resin composition cannot be maintained, and the hardness may increase. Therefore, the amount of the filler is preferably 60% by volume or less of the entire epoxy resin composition.

  Although the average particle diameter of a filler is not specifically limited, For example, it is preferable that they are 0.5 micrometer-50 micrometers. When the average particle diameter of the filler is within this range, the filler is easily highly dispersed in the epoxy resin composition. That is, when the average particle diameter is within this range, the viscosity of the resin can be prevented from becoming excessively high, and the fluidity of the resin is ensured, so that workability and moldability are improved. In addition, the average particle diameter of the filler is preferably 0.5 μm to 20 μm, more preferably 1 μm to 10 μm.

  The average particle diameter of the filler contained in the epoxy resin composition can be measured by baking the epoxy resin composition and isolating the filler. In the present specification, “average particle diameter” means a median diameter. The median diameter means a particle diameter (d50) at which an integrated (cumulative) weight percentage is 50%. The median diameter can be measured using, for example, a laser diffraction particle size distribution measuring apparatus “SALD2000” (manufactured by Shimadzu Corporation).

  The shape of the filler is not particularly limited, and may be, for example, spherical or polyhedral, or may be a plate having a thin shape such as a scale shape, a flake shape, or a flake shape. However, the filler is preferably spherical. By having such a shape, it becomes easy to highly disperse the filler in the epoxy resin composition.

  In order to improve the compatibility and adhesiveness with the resin, the filler may be subjected to a surface treatment such as a coupling treatment or by adding a dispersing agent to improve the dispersibility in the epoxy resin composition. Good. In addition, by appropriately selecting the surface treatment agent, the filler can be distributed more effectively in the phase separation structure.

  For the surface treatment, organic surface treatment agents such as fatty acids, fatty acid esters, higher alcohols, and hardened oils can be used. In addition, an inorganic surface treatment agent such as a silicone oil, a silane coupling agent, an alkoxysilane compound, or a silylated material can also be used for the surface treatment. By using these surface treatment agents, water resistance may be improved, and dispersibility in the resin may be further improved. Although it does not specifically limit as a processing method, There exist (1) dry method, (2) wet method, (3) integral blend method etc.

(1) Dry method The dry method is a method in which a surface treatment agent is dropped onto a surface treatment agent while stirring the filler by mechanical stirring such as a Henschel mixer, a Nauter mixer, or a vibration mill. . When silane is used as the surface treatment agent, a solution obtained by diluting silane with an alcohol solvent, a solution obtained by diluting silane with an alcohol solvent, further adding water, diluting silane with an alcohol solvent, and further adding water and an acid. Can be used. The preparation method of the surface treatment agent is described in the catalog of the manufacturer of the silane coupling agent, but the preparation method is appropriately determined depending on the hydrolysis rate of silane and the type of filler.

(2) Wet method The wet method is a method in which a filler is directly immersed in a surface treatment agent. The surface treatment agent that can be used is the same as in the dry method. The method for preparing the surface treatment agent is the same as the dry method.

(3) Integral blend method The integral blend method is a method of diluting a surface treatment agent with a stock solution or alcohol, etc., and directly adding it into a mixer when stirring the resin and filler. The preparation method of the surface treatment agent is the same as that of the dry method and wet method, but the amount of the surface treatment agent in the case of the integral blend method is generally larger than that of the dry method and wet method.

  In the dry method and the wet method, the surface treatment agent is dried as necessary. When a surface treatment agent using alcohol or the like is added, it is necessary to volatilize the alcohol. If alcohol eventually remains in the formulation, the alcohol is generated as a gas that adversely affects the polymer content. Therefore, it is preferable that the drying temperature be equal to or higher than the boiling point of the solvent used. Furthermore, when silane is used as the surface treatment agent, it can be heated to a high temperature (for example, 100 ° C. to 150 ° C.) using an apparatus in order to quickly remove the silane that has not reacted with the filler. preferable. However, considering the heat resistance of the silane, it is preferable to keep the temperature below the decomposition point of the silane. The treatment temperature is preferably about 80 to 150 ° C., and the treatment time is preferably 0.5 to 4 hours. By appropriately selecting the drying temperature and time according to the amount of treatment, it is possible to remove the solvent and unreacted silane.

When silane is used as the surface treatment agent, the amount of silane necessary to treat the surface of the filler can be calculated by the following equation.
[Silane amount (g)] = [Amount of filler (g)] × [Specific surface area of filler (m ² / g)] / [Minimum silane coverage (m ² / g)]

The “minimum coverage area of silane” can be obtained by the following calculation formula.
[Minimum coverage area of silane (m ² /g)]=(6.02×10 ²³ ) × (13 × 10 ⁻²⁰ (m ² )) / [Molecular weight of silane]
In the formula, “6.02 × 10 ²³ ” is an Avogadro constant, and “13 × 10 ⁻²⁰ ” is an area (0.13 nm ² ) covered by one molecule of silane.

  The necessary silane amount is preferably 0.5 times or more and less than 1.0 times the silane amount calculated by this calculation formula. Even if the amount of silane is 1.0 times or more, the effect of this embodiment can be exhibited. However, when the amount of silane is 1.0 times or more, an unreacted component remains, which may cause deterioration of physical properties such as deterioration of mechanical properties and water resistance. Therefore, the upper limit is preferably less than 1.0 times. Moreover, the reason why the lower limit value is set to 0.5 times the amount calculated by the above formula is that even this amount is sufficiently effective in improving the filler filling property into the resin.

  The epoxy resin composition of the present embodiment may contain additives as long as the effects of the present embodiment are not impaired. Specifically, the epoxy resin composition includes a colorant, a flame retardant, a flame retardant aid, a fiber reinforcing material, a viscosity reducing agent for adjusting viscosity in production, and a toner (colorant) for improving dispersibility. A dispersion adjusting agent, a release agent and the like may be included. These may be known ones, and examples thereof include the following.

  As the colorant, for example, an inorganic pigment such as titanium oxide, an organic pigment, or a toner containing them as a main component can be used. These may be used individually by 1 type and may be used in combination of 2 or more types.

  Examples of the flame retardant include organic flame retardants, inorganic flame retardants, and reactive flame retardants. These may be used individually by 1 type and may be used in combination of 2 or more types. In addition, when making an epoxy resin composition contain a flame retardant, it is preferable to use a flame retardant adjuvant together. Flame retardant aids include antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, antimony tartrate and other antimony compounds, zinc borate, barium metaborate, hydrated alumina, zirconium oxide, polyphosphoric acid Examples include ammonium, tin oxide, and iron oxide. These may be used individually by 1 type and may be used in combination of 2 or more types.

  Thus, the epoxy resin composition of this embodiment contains an epoxy resin, a curing agent, and liquid rubber. And when the said epoxy resin composition hardens | cures, the phase-separation structure isolate | separated into the 2 or more phase was formed, and the hardness measured with the type E durometer prescribed | regulated to JISK6253 is 80 or less. Thus, since the epoxy resin composition of the present embodiment has a phase separation structure composed of a plurality of phases in which the contents of the epoxy resin and the liquid rubber are relatively different, the hardness is lowered and the flexibility is reduced. It becomes possible to raise.

  In addition, it is preferable that the epoxy resin composition has a hardness measured by a type E durometer defined in Japanese Industrial Standard JIS K6253 (vulcanized rubber and thermoplastic rubber-how to obtain hardness) of 80 or less, and 70 or less. It is more preferable that When the hardness of the epoxy resin composition is 80 or less, it can be suitably used for, for example, an adhesive or a sealing material for a semiconductor element. In addition, although the minimum of the hardness of an epoxy resin composition is not specifically limited, For example, it is preferable that the hardness measured with the type E durometer prescribed | regulated to JISK6253 is 3 or more.

  The epoxy resin composition of the present embodiment having high flexibility can be suitably used for adhesives, electronic substrates, heat dissipation members, and other electronic devices. Moreover, it is also preferable to seal members, such as a semiconductor element, using the said epoxy resin composition.

  Next, the manufacturing method of the epoxy resin composition of this embodiment is demonstrated. First, an epoxy resin, a curing agent and liquid rubber are added and kneaded to produce an uncured resin composition. At this time, a filler is added as necessary. The kneading of each component may be performed in a single stage, or may be performed in multiple stages by sequentially adding each component. When adding each component sequentially, it can add in arbitrary orders.

  As a method for kneading and adding each component, for example, first, a part or all of the liquid rubber is kneaded with an epoxy resin to adjust the viscosity. Next, the remaining liquid rubber, curing agent, filler and additive are kneaded sequentially. The order of addition is not particularly limited, but the curing agent is preferably added last from the viewpoint of the storage stability of the resin composition.

  As described above, additives such as a colorant, a flame retardant, a flame retardant aid, a fiber reinforcement, a viscosity reducer, a dispersion regulator, and a release agent are added to the resin composition as necessary. Also good. Also, the order of addition of these additives is not particularly limited and can be added at an arbitrary stage. However, as described above, the curing agent is preferably added last.

  A conventionally well-known thing can be used as a kneading machine apparatus used for manufacture of a resin composition. Specific examples include a roll mill, a planetary mixer, a kneader, an extruder, a Banbury mixer, a mixing vessel provided with a stirring blade, and a horizontal mixing vessel.

  The kneading temperature at the time of producing the resin composition is not particularly limited as long as it can be kneaded, but for example, a range of 10 to 150 ° C is preferable. When it exceeds 150 degreeC, the partial hardening reaction of an epoxy resin and a hardening | curing agent will start, and the storage stability of the resin composition obtained may fall. If it is lower than 10 ° C., the viscosity of the resin composition is high, and it may be difficult to knead substantially. Preferably it is 20-120 degreeC, More preferably, it is the range of 30-100 degreeC.

  The molding method of the uncured resin composition can be any method, and the molding shape can be any shape. For example, various means such as compression molding (direct pressure molding), transfer molding, injection molding, extrusion molding, and screen printing can be used as the molding means. Finally, the epoxy resin composition of this embodiment can be obtained by heating the resin composition to cause the epoxy resin and the curing agent to react and cure.

  Thus, the epoxy resin composition of this embodiment knead | mixes an epoxy resin, a hardening | curing agent, and liquid rubber first. At this time, the epoxy resin and the liquid rubber are in a mutually compatible state. And when an epoxy resin and a hardening | curing agent react and harden | cure by heating, the compatibility of these resin falls and it phase-separates into an epoxy resin rich phase and a liquid rubber rich phase. However, as described above, even when the epoxy resin and the curing agent react to form a phase structure, the liquid rubber remains inside the epoxy resin rich phase, so that the flexibility of the epoxy resin rich phase is increased, The flexibility of the resulting epoxy resin composition can be improved.

  Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples, but the present embodiment is not limited to these examples.

  In producing the resin compositions of Examples and Comparative Examples, the following epoxy resins, curing agents, liquid rubbers and fillers were used.

[Epoxy resin]
(1) Epoxy resin A (bisphenol A type diglycidyl ether (DGEBA), jER (registered trademark) 834 manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 250 g / eq)
(2) Epoxy resin B (bisphenol A type diglycidyl ether (DGEBA), jER (registered trademark) 1001 manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 474 g / eq)

[Curing agent]
Polyetheramine (polyoxypropylenediamine, Huntsman's Jeffamine (registered trademark) D2000, active hydrogen equivalent: 514 g / eq)

[Liquid rubber]
Hydroxyl-terminated liquid butadiene rubber (Poly bd (registered trademark) R-45HT manufactured by Idemitsu Kosan Co., Ltd.)

[Filler]
Alumina (Alumina Beads (registered trademark) CB-A09S, Showa Denko KK, average particle size: 9 μm)

[Example 1]
First, the resin mixture was obtained by adding a hardening | curing agent and liquid rubber to the heated epoxy resin B by the compounding quantity shown in Table 1. Next, the resin mixture was put into a mold heated to 150 ° C., and held in a drying oven at 150 ° C. for 4 hours to obtain a resin plate of this example. In addition, the thickness of the obtained resin plate was 12 mm.

[Example 2]
As shown in Table 1, a resin plate of this example was obtained in the same manner as in Example 1 except that the blending amount was changed. In addition, the thickness of the obtained resin plate was 12 mm.

[Example 3]
First, the resin mixture was obtained by adding a hardening | curing agent, liquid rubber, and a filler to the heated epoxy resin A and the epoxy resin B with the compounding quantity shown in Table 1. Next, the resin mixture was put into a mold heated to 150 ° C., and held in a drying oven at 150 ° C. for 4 hours to obtain a resin plate of this example. In addition, the thickness of the obtained resin plate was 12 mm.

[Example 4]
As shown in Table 1, a resin plate of this example was obtained in the same manner as in Example 3 except that the blending amount was changed. In addition, the thickness of the obtained resin plate was 12 mm.

[Comparative Example 1]
First, the resin mixture was obtained by adding a hardening | curing agent to the epoxy resin B heated with the compounding quantity shown in Table 1. Next, the resin mixture was put into a mold heated to 150 ° C., and held in a drying oven at 150 ° C. for 4 hours to obtain a resin plate of this example. In addition, the thickness of the obtained resin plate was 12 mm.

[Comparative Example 2]
First, the resin mixture was obtained by adding a hardening | curing agent and a filler to the heated epoxy resin A and the epoxy resin B with the compounding quantity shown in Table 1. Next, the resin mixture was put into a mold heated to 150 ° C., and held in a drying oven at 150 ° C. for 4 hours to obtain a resin plate of this example. In addition, the thickness of the obtained resin plate was 12 mm.

[Comparative Example 3]
As shown in Table 1, a resin plate of this example was obtained in the same manner as in Comparative Example 2 except that the blending amount was changed. In addition, the thickness of the obtained resin plate was 12 mm.

  Table 1 shows the compounding amount (parts by mass) of the epoxy resin, the curing agent, the liquid rubber (butadiene rubber), and the filler (alumina) in each example. Moreover, the volume ratio (vol%) of the liquid rubber in the whole resin board calculated | required from the specific gravity of an epoxy resin, a hardening | curing agent, liquid rubber, and a filler, the volume ratio (vol%) of the liquid rubber in a resin component, in the whole resin board The volume ratio (vol%) of alumina is also shown.

[Evaluation]
For each resin plate obtained in Examples 1 to 4 and Comparative Examples 1 to 3, hardness was measured as follows, and cross-sectional observation and component analysis were also performed.

(Hardness measurement)
For each of the resin plates obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the hardness was measured using a type E durometer according to JIS K6253. The measurement results are shown in Table 1.

(Cross section observation)
With respect to the resin plates obtained in Examples 1 and 2, first, an observation cross section was prepared using a cross section polisher (registered trademark, SM-09010 manufactured by JEOL Ltd.). And after cross-section formation, cross-sectional observation was performed using the laser microscope (Keyence Corporation laser microscope VK-9700). The observation result of the resin plate of Example 1 is shown in FIG. 2, and the observation result of the resin plate of Example 2 is shown in FIG.

  For the resin plates obtained in Examples 3 and 4, an observation cross section was first prepared by mechanical polishing. And after cross-section formation, cross-section observation was performed using the scanning electron microscope (3D real surface view microscope VE-9800 by Keyence Corporation). The observation result of the resin plate of Example 3 is shown in FIG. 8, and the observation result of Example 4 is shown in FIG.

(Component analysis)
Using the microscopic laser Raman analyzer (manufactured by HORIBA JOBIN YVON, microscopic laser Raman spectrometer LabRAM HR-800), the phase separation structure was observed on the observation cross sections of the resin plates of Examples 1 and 2 prepared by the above method. The resin component to be formed was identified. The analysis results of the resin plate of Example 1 are shown in FIGS. 3 and 4, and the analysis results of Example 2 are shown in FIGS. 6 and 7.

  Here, FIG. 3 (a) is a micrograph of the resin plate of Example 1, and FIG. 3 (b) is a graph showing Raman spectra at points a) and b) in FIG. 3 (a). 4A shows a Raman mapping image derived from a benzene ring (DGEBA), and FIG. 4B shows a Raman mapping image derived from a C═C bond (butadiene). 6A is a photomicrograph of the resin plate of Example 2, and FIG. 6B is an enlarged photo of a range indicated by reference sign B in FIG. 6A. FIG. 6C is a graph showing Raman spectra at points a) and b) in FIG. FIG. 7A shows a Raman mapping image derived from a benzene ring (DGEBA), and FIG. 7B shows a Raman mapping image derived from a C═C bond (butadiene).

(Contrast between the resin plate of Examples 1 and 2 and the resin plate of Comparative Example 1)
From Table 1, the resin plates of Examples 1 and 2 were lower in hardness than the resin plate of Comparative Example 1 and exhibited high flexibility. The reason why the resin plates of Examples 1 and 2 showed higher flexibility than Comparative Example 1 is estimated as follows.

  As shown in FIG. 2, as a result of cross-sectional observation, it can be seen that the resin plate of Example 1 has a phase separation structure, and further forms a sea island structure having a sea phase 3 and an island phase 4. As a result of Raman spectroscopic analysis of the cross section, as shown in FIG. 3, in the sea phase a), a peak derived from the stretching vibration of the benzene ring is observed, and in the island phase b), it originates from the stretching vibration of C = C bond. A peak was observed. That is, a peak derived from DGEBA containing a benzene ring was observed in sea phase a), and a peak derived from liquid rubber containing butadiene was observed in island phase b). From this result, it can be seen that the resin plate of Example 1 forms a sea-island structure composed of a sea phase composed of an epoxy resin-rich phase and an island phase composed of a liquid rubber-rich phase.

  4A shows that the epoxy resin (DGEBA) exists as a main component in the sea phase 3, and that butadiene rubber exists as the main component in the island phase 4 from FIG. 4B. Furthermore, from FIG. 4B, it can be seen that the butadiene rubber is contained somewhat in the sea phase 3 mainly composed of epoxy resin. Thus, since the flexible butadiene rubber component is contained not only in the island phase 4 but also in the sea phase 3, it is estimated that the flexibility of the resin plate of Example 1 is improved.

  Further, as shown in FIG. 5, as a result of cross-sectional observation, it can be seen that the resin plate of Example 2 also has a phase separation structure, and further forms a sea island structure having a sea phase 5 and an island phase 6. As a result of the Raman spectroscopic analysis of the cross section, as shown in FIG. 6, a peak derived from the stretching vibration of the benzene ring is observed in the island phase a), and the C = C bond in the vicinity of the boundary between the island phase and the sea phase b). A peak derived from the stretching vibration of was observed. That is, a peak derived from DGEBA containing a benzene ring was observed in the island phase a), and a peak derived from a liquid rubber containing butadiene was observed near the boundary between the island phase and the sea phase b). From this result, it can be seen that the resin plate of Example 2 forms a sea-island structure composed of an island phase composed of an epoxy resin-rich phase and a sea phase composed of a liquid rubber-rich phase.

  7A shows that the epoxy resin (DGEBA) exists as a main component in the island phase 6, and that butadiene rubber exists as the main component in the sea phase 5 from FIG. 7B. Thus, since the flexible butadiene rubber component forms a continuous phase, it is estimated that the flexibility of the resin plate of Example 2 is further improved than that of Example 1.

(Contrast between the resin plate of Example 3 and the resin plate of Comparative Example 2)
From Table 1, the resin plate of Example 3 was low in hardness and high in flexibility compared with the resin plate of Comparative Example 2 even though the volume ratio of the filler was the same. Further, as shown in FIG. 8, as a result of cross-sectional observation, it can be seen that the resin plate of Example 3 also has a phase separation structure, and further forms a sea island structure having a sea phase 7 and an island phase 8.

  As a result of Raman spectroscopic analysis of the cross section, a peak derived from the stretching vibration of the benzene ring was observed in the island phase 8, and a peak derived from the stretching vibration of the C = C bond was observed in the sea phase 7. That is, in the island phase 8, a peak derived from DGEBA containing a benzene ring was observed, and in the sea phase 7, a peak derived from a liquid rubber containing butadiene was observed. From this result, it was found that the resin plate of Example 3 formed a sea-island structure composed of a sea phase 7 composed of a liquid rubber-rich phase and an island phase 8 composed of an epoxy resin-rich phase.

  As a result of FIG. 8 and Raman spectroscopic analysis, it was found that the filler 9 was unevenly distributed in the liquid rubber-rich phase that is the sea phase 7. From these results, the reason why the resin plate of Example 3 is higher in flexibility than Comparative Example 2 is that the phase separation structure composed of the epoxy resin rich phase and the liquid rubber rich phase is retained even if the filler component is contained. It is speculated that it has been.

(Contrast between the resin plate of Example 4 and the resin plate of Comparative Example 3)
From Table 1, the resin plate of Example 4 was low in hardness and high in flexibility compared with the resin plate of Comparative Example 3 even though the volume ratio of the filler was the same. Further, as shown in FIG. 9, as a result of cross-sectional observation, the resin plate of Example 4 also has a phase separation structure, and further forms a co-continuous structure having one phase 10 and the other phase 11. I understand.

  As a result of the Raman spectroscopic analysis of the cross section, a peak derived from the stretching vibration of the benzene ring is observed in one phase 10 of the co-continuous structure, and a peak derived from the stretching vibration of the C = C bond is observed in the other phase 11. It was done. That is, in one phase 10, a peak derived from DGEBA containing a benzene ring was observed, and in the other phase 11, a peak derived from a liquid rubber containing butadiene was observed. From this result, it was found that the resin plate of Example 4 formed a co-continuous structure composed of an epoxy resin rich phase (one phase 10) and a liquid rubber rich phase (the other phase 11). .

  As a result of FIG. 9 and Raman spectroscopic analysis, it was found that the filler 12 was unevenly distributed in the other phase 11 (liquid rubber rich phase). And from these results, the reason why the resin plate of Example 4 is higher in flexibility than Comparative Example 3 is that the phase separation structure composed of the epoxy resin-rich phase and the liquid rubber-rich phase is retained even if the filler component is contained. It is speculated that it has been.

  Moreover, from Example 3 and Example 4, it can be understood that the phase separation structure can be formed with both the sea-island structure and the co-continuous structure, and can be freely selected.

  The entire contents of Japanese Patent Application No. 2015-097842 (filing date: May 13, 2015) are incorporated herein by reference.

  Although the contents of the present invention have been described with reference to the embodiments, the present invention is not limited to these descriptions, and it is obvious to those skilled in the art that various modifications and improvements can be made.

  Since the epoxy resin composition of the present invention has a phase separation structure having a phase mainly composed of epoxy resin and a phase mainly composed of liquid rubber, the hardness can be lowered and the flexibility can be increased. It becomes possible.

Claims (6)

An epoxy resin composition containing an epoxy resin, a curing agent, and liquid rubber,
An epoxy having a phase separation structure separated into two or more phases when the epoxy resin composition is cured, and having a hardness measured by a type E durometer defined in JIS K6253 of 80 or less. Resin composition.   The epoxy resin composition according to claim 1, wherein the epoxy resin is a bisphenol A type epoxy resin, and the curing agent is an aliphatic amine.   The epoxy resin composition according to claim 1 or 2, wherein the liquid rubber contains at least one selected from the group consisting of butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, and styrene-butadiene rubber. .   The epoxy resin composition according to any one of claims 1 to 3, wherein a terminal of a molecule in the liquid rubber has a hydroxy group.   The epoxy resin composition according to claim 1, further comprising a filler. The cured epoxy resin composition includes a first resin phase in which a first resin is three-dimensionally continuous, and a phase including a second resin phase that is different from the first resin phase and is formed of a second resin. Having a separation structure,
The content of the liquid rubber contained in one of the first resin and the second resin is greater than the content of the liquid rubber contained in the other of the first resin and the second resin. The epoxy resin composition according to any one of claims 1 to 5.